Buggy code:
public class JsonFieldProcessor extends Processor { public JsonFieldProcessor ( ProcessingEnvironment processingEnv ) { } @ Override public Class getAnnotation ( ) { } @ Override public void findAndParseObjects ( RoundEnvironment env , Map < String , JsonObjectHolder > jsonObjectMap , Elements elements , Types types ) { } private void processJsonFieldAnnotation ( Element element , Map < String , JsonObjectHolder > jsonObjectMap , Elements elements , Types types ) { } private boolean isJsonFieldFieldAnnotationValid ( Element element , Elements elements ) { } private boolean ensureTypeConverterClassValid ( TypeMirror typeConverterClassMirror , Elements elements , Types types ) { TypeElement typeConverterElement = elements . getTypeElement ( typeConverterClassMirror . toString ( ) ) ; if ( typeConverterElement != null ) { boolean isTypeConverterType = false ; TypeElement element = typeConverterElement ; while ( ( ! isTypeConverterType ) && ( element != null ) ) { for ( TypeMirror iface : element . getInterfaces ( ) ) { <START_BUG> if ( iface . toString ( ) . equals ( ( ( TypeConverter . class . getCanonicalName ( ) ) + "<T>" ) ) ) { <END_BUG> isTypeConverterType = true ; } } TypeMirror superClassMirror = element . getSuperclass ( ) ; if ( superClassMirror != null ) { superClassMirror = types . erasure ( superClassMirror ) ; element = elements . getTypeElement ( superClassMirror . toString ( ) ) ; } else { element = null ; } } if ( ! isTypeConverterType ) { error ( element , "TypeConverter<seq2seq4repair_space>elements<seq2seq4repair_space>must<seq2seq4repair_space>implement<seq2seq4repair_space>the<seq2seq4repair_space>TypeConverter<seq2seq4repair_space>interface<seq2seq4repair_space>or<seq2seq4repair_space>extend<seq2seq4repair_space>from<seq2seq4repair_space>one<seq2seq4repair_space>of<seq2seq4repair_space>the<seq2seq4repair_space>convenience<seq2seq4repair_space>helpers<seq2seq4repair_space>(ie<seq2seq4repair_space>StringBasedTypeConverter<seq2seq4repair_space>or<seq2seq4repair_space>DateTypeConverter)." ) ; return false ; } boolean constructorIsDeclared = false ; boolean hasAccessibleConstructor = false ; List < ? extends Element > enclosedElements = typeConverterElement . getEnclosedElements ( ) ; for ( Element enclosedElement : enclosedElements ) { ElementKind enclosedElementKind = enclosedElement . getKind ( ) ; if ( enclosedElementKind == ( ElementKind . CONSTRUCTOR ) ) { constructorIsDeclared = true ; if ( ! ( enclosedElement . getModifiers ( ) . contains ( Modifier . PRIVATE ) ) ) { ExecutableElement executableElement = ( ( ExecutableElement ) ( enclosedElement ) ) ; if ( ( executableElement . getParameters ( ) . size ( ) ) == 0 ) { hasAccessibleConstructor = true ; } } } } if ( constructorIsDeclared && ( ! hasAccessibleConstructor ) ) { error ( element , "TypeConverter<seq2seq4repair_space>classes<seq2seq4repair_space>must<seq2seq4repair_space>have<seq2seq4repair_space>a<seq2seq4repair_space>non-private<seq2seq4repair_space>zero<seq2seq4repair_space>argument<seq2seq4repair_space>constructor." ) ; return false ; } } return true ; } }

Fix:
if ( types . erasure ( iface ) . toString ( ) . equals ( TypeConverter . class . getCanonicalName ( ) ) ) {